Field of the Invention
The present invention relates to an electrophotographic image forming apparatus.
Description of Related Art
In general, an electrophotographic image forming apparatus (such as a printer, a copy machine, and a fax machine) is configured to irradiate (expose) a uniformly-charged photoconductor (for example, a photoconductor drum) with (to) laser light based on image data to form an electrostatic latent image on the surface of the photoconductor. The electrostatic latent image is then visualized by supplying toner from a developing device to the photoconductor on which the electrostatic latent image is formed, whereby a toner image is formed. Further, the toner image is directly or indirectly transferred to a sheet through an intermediate transfer belt, followed by heating and pressurization for fixing, whereby an image is formed on the sheet.
The above-described image forming apparatus includes a sheet conveyance section that conveys to an image forming section a sheet fed from a sheet feeding section (which includes sheet feed tray, manual sheet feeding section, an external sheet feeding device, and the like). The sheet conveyance section includes a plurality of conveyance roller sections, and at least one of the conveyance roller sections sandwiches a sheet when conveying the sheet. The sheet feeding path of the image forming apparatus includes a sheet feeding path on the sheet feeding side (hereinafter referred to as “sheet feeding path”), a sheet feeding path of the sheet conveyance section (hereinafter referred to as “conveyance path”), and a sheet feeding path on the ejection side (hereinafter referred to as “sheet ejection path”).
Typically, when a jam has occurred in a sheet feeding path, the user pinches the leading end portion of the sheet remaining in the sheet feeding path and pulls out the sheet to the sheet ejection side, or the user pinches the rear end portion of the sheet and pulls out the sheet to the sheet feeding side, to remove the sheet. In addition, a technique has been proposed in which a sheet is cut such that the sheet is divided into a part on which a toner image is transferred and a part on which no toner image is transferred, and the former part is removed from the sheet ejection side whereas the latter part is removed from the sheet feeding side, thereby preventing unfixed toner from being attached on a registration roller and the like on the sheet feeding side (for example, PTL 1: Japanese Patent Application Laid-Open No. 10-20593).
In recent years, an image forming apparatus has been practically used in which a sheet conveyance section configured to invert a sheet for both-side printing is mounted as a sheet conveyance unit (so-called Auto-Duplex Unit (ADU)). In such an image forming apparatus, the conveyance path in the sheet conveyance unit is detachable from the image forming apparatus, but a sheet feeding path and a sheet ejection path are fixed to the image forming apparatus main body.
When a jam has occurred in such an image forming apparatus, the sheet conveyance unit is pulled out from the image forming apparatus main body to perform unjamming. Various members (for example, a guide member) provided to the sheet feeding path can be exposed by pulling out the sheet conveyance unit from the image forming apparatus, and thus a sheet can be carefully removed from an suitable place so as not to scatter unfixed toner.
On the other hand, depending on the location of a jam, the length of the sheet feeding path, and the sheet length, the sheet may protrude from the sheet conveyance unit into the sheet feeding path or the sheet ejection path. When the sheet conveyance unit is pulled out of the image forming apparatus main body in this state, the sheet tears and breaking occurs. For this reason, the sheet conveyance unit is pulled out after the sheet is sent into the sheet conveyance unit by a conveyance roller section.
When a jam has occurred during image formation using flat sheets, breaking can be prevented by the above-described way. However, when a jam has occurred during image formation using a long sheet, the long sheet cannot be sent into the sheet conveyance unit, and the breaking cannot be easily prevented in many cases. If a space for sending the entirety of a long sheet is ensured in the sheet conveyance unit, the size of the apparatus may possibly be increased.
In addition, unjamming may be performed by pulling out the long sheet to the sheet feeding side or the sheet ejection side after the long sheet is cut in the image forming apparatus in which the technology disclosed in PTL 1 is applied. In this case, however, since an unfixed toner image is formed on the part pulled out from the sheet ejection side, scattering of toner or the like may possibly occur at the time when the sheet is pulled out.